Oil & Water - the horrible mix

I've been trying to determine the concentration of a vegie oil (0.9 g/mL) in dilute(~2,4 w%) oil-water emulsions that are badly aerated and with gas bubbles.

I tried the density method, weighing the samples and then vacuum suck them to rid the bubbles - in order to get an accurate volume reading. But then I realized that water was vaporizing a little. and the dilute samples make the determination really hard.